Device for adjustment of a line sensor in a film scanner

ABSTRACT

The invention relates to a device for adjustment of a line sensor in a film scanner. A glass disk is arranged between each emitting surface of a color separator and the respective line sensor. Said disk may be rotated in two directions, out of a plane lying perpendicular to the beam direction, such that the light emitted from the glass disc is displaced, depending on the angle of the rotation.

This application claims the benefit under 35 U.S.C. § 365 ofInternational Application PCT/EP01/08033 filed Jul. 12, 2001, whichclaims the benefit of German Application No. 200 12 733.0, filed Jul.22, 2000.

The invention relates to an apparatus for adjusting a line sensor in afilm scanner.

BACKGROUND OF THE INVENTION

Film scanners are appliances in which the film is scanned optically inorder to obtain video signals which can be processed, transmitted orstored once again. Various physical forms have become known for thispurpose. In one of these physical forms, the film is imaged for colourscanning by means of a suitable objective and a colour splitter ontothree line sensors—also referred to as CCD sensors. The images are thenscanned line-by-line by moving the film, with the scanning in the linedirection being carried out by clocked reading in the individualelements of the line sensor.

Convergence errors, which are also referred to as registration errorsand which can be seen in the form of coloured edges when the videosignals are reproduced, can occur between the three primary colours red,green and blue as a result of tolerances of the optical elements andinaccuracies in the mounting of the line sensor on a holder.

SUMMARY OF THE INVENTION

The object of the present invention is to provide an apparatus whichallows very accurate fine adjustment of the position of the images onthe line sensors.

This object is achieved according to the invention in that a glass paneis arranged between in each case one outlet surface of a colour splitterand the respective line sensor and can be pivoted in two directions outof a plane lying at right angles to the beam direction, so that thelight emerges offset from the glass pane as a function of the pivotingangle.

The invention has the advantage that the three primary colours of a filmimage are set in position with pinpoint accuracy, and can thus be madeto coincide. A further advantage is that the apparatus according to theinvention can not only be produced at low cost, but is alsotemperature-stable.

One advantageous refinement of the invention consists in that dependingon the pivoting direction, the glass pane is mounted on two contactpoints in a housing, and the pivoting directions are essentially atright angles to one another, with one contact point being providedjointly for both pivoting directions. The position of the three primarycolours can thus be adjusted independently of one another in thehorizontal and vertical directions.

One advantageous embodiment of the invention consists in that the glasspane is held firmly in a metal plate which can pivot and has an inclinefor each pivoting direction, on which incline an adjusting screw, whichis arranged in a housing, acts against the force of a spring force whichacts between the metal plate and the housing. In addition to the alreadymentioned advantages, this embodiment is distinguished by the fact thatthe adjusting screws are easily accessible and can be operated from adirection at right angles to the respective optical axis.

A further advantageous refinement of the apparatus according to theinvention not only allows the positions of the images to be adjusted,but also allows adjustment of the focusing for each individual linesensor, in that the line sensor is arranged on a mount which can pivotabout an axis parallel to the lines. In this refinement as well, easyaccessibility to the adjusting screws can be achieved in that the mountis provided with an incline on the side of the line sensor opposite thepivoting axis, on which incline an adjusting screw acts against a springforce.

A further requirement for correct scanning of the film images is thatall the line sensors are at the same angle, which means that therespectively scanned lines are parallel to the frame line. In order tocorrect any errors relating to this, one development of the inventionprovides that the line sensor is arranged on the mount by means of asensor holder, in that the sensor holder has two pins in an extension ofthe longitudinal axis (line direction) of the line sensor, which pinsproject into holes in the mount and have play at right angles to theline direction, and in that an adjusting screw projects from each of thetwo sides into the hole.

One of the pins is defined as a reference point with respect to theline. In order that this pin is located in the correct position in theline direction when it is inserted into the mount, the development canbe triggered such that the pins are flattened on one side.

BRIEF DESCRIPTION OF THE DRAWINGS

One exemplary embodiment of the invention will be explained in moredetail in the following description and is illustrated in a number offigures in the drawing, in which:

FIG. 1 shows the parts of a film scanner which are necessary to explainthe invention,

FIG. 2 shows a glass pane which can be pivoted in order to adjust thehorizontal and vertical position of the film line which is imaged on theline sensor, and

FIG. 3 shows an apparatus for adjusting the focusing and the rotationposition of the line sensor.

Identical parts are provided with the same reference symbols in thefigures.

DETAILED DESCRIPTION

A colour splitter 1, which is formed from prisms, splits the colouredimage supplied to the inlet surface 2 from a respective film, which isnot shown, into the three primary colours, red, green and blue, whichemerge at outlet surfaces 3, 4, 5 from the colour splitter. Each ofthese colour outlet openings is associated with a line sensor andassociated adjusting and mounting elements. For the sake of clarity,these elements and the line sensor are shown for only one of the outletsurfaces. The colour splitter 1 is located on a mounting block 6, whichhas a mounting surface 7, 8, 9 for in each case one of the outletsurfaces 3, 4, 5.

To allow the items to be identified better, the other elementsillustrated in FIG. 1 are shown in the form of an exploded illustration.The light which emerges from the outlet surface 4 of the colour splitter1 first of all passes through a glass pane 11, which is used forposition correction and is mounted in a housing 12 such that it can bepivoted in two directions. In the assembled state, the housing 12 isscrewed to a mounting plate 13, which is in turn screwed to the mountingsurface 8 of the mounting block 6.

The mounting plate contains a mount 14 for the line sensor 15, which isconnected to the mount 14 via a sensor holder 16 such that pins 17, 18enter corresponding holes 19, 20 in the mount 14. Pins are likewiselocated on the rear face of the sensor holder 16, and are used for themounting of a printed circuit board 21. The printed circuit board 21furthermore has holes 22 for the connecting pins 23 of the line sensor15, and a range of circuits, which are not illustrated, for operation ofthe line sensor.

FIG. 2 shows details of the position adjusting device with the glasspane 11 and the housing 12. The glass pane 11 is firmly connected to ametal plate 31 which has three cutouts 32, 33, 34 for pins 35, 36, 37which project into the cutouts, fixed to the housing. The pin 37 isprovided with a head which projects beyond the opening 34, although thisis not illustrated in FIG. 2, for the sake of clarity. Springs, whichare likewise not illustrated, exert a force on the metal plate 31.

The metal plate 31 is prevented from falling out firstly by the head(which is not illustrated) of the pin 37 and secondly by two integrallyformed inclines 38, 39, which interact with adjusting screws 40, 41.Lock nuts 42, 43 are used for fixing the screws once the adjustmentprocess has been completed. For vertical adjustment, that is to say atright angles to the line direction, the screw 41 is rotated, with themetal plate 31 and hence the glass pane 11 being pivoted about the pointat 37 and the contact point of the screw 40 with the incline 38.

Once the vertical position has been set, the horizontal position can beadjusted by means of the screw 40, with the pivoting axis then beingformed by the point 37 and the contact point of the screw 41 with theincline 39. Since the pivoting axes are virtually parallel to oneanother, the adjustment processes can be carried out independently ofone another.

FIG. 3 shows the apparatus for focus adjustment and for rotationposition adjustment of the line sensor. In addition to the mountingplate 13, this has a mount 14, which can pivot about an axis runningparallel to the line direction. Suitable holes 51 to 54 are provided forthis purpose in the mounting plate 13 and in the mount, and suitablelocating pins are located in these holes 51 to 54 in the assembledstate. The mount 14 can then be pivoted like a door. The pivotingmovement is set by an incline 55 together with adjusting screw 56, witha spring (which is not illustrated) pressing the mount or the incline 55against the tip of the adjusting screw 56. It is thus possible to adjustthe focus by rotating the adjusting screw 56.

As already described in conjunction with FIG. 1, the sensor holder 16 ismounted together with the sensor 15 by means of two pins 17, 18 in holes19, 20 in the mount 14. The pins are flattened on one side and have asomewhat smaller diameter than the holes 19 and 20, into which threadedholes 61 to 64 in each case open from two sides. Further adjustingscrews, which cannot be seen in FIG. 3, are located in these threadedholes 61 to 64 and act on the pins 17, 18 (FIG. 1) from both sides, sothat lateral adjustment can be carried out in each of the holes 19, 20,with adjustment in the opposite direction resulting in the line sensorbeing rotated.

The pin 17 is defined as a reference point with respect to the line. Inorder that this pin adopts the correct position in the line directionduring insertion into the mount 14, at least the pin 17 is flattened onone side. The edges of the flattened region, which are then defined bythe adjusting screw in the threaded hole 64, are pressed against thewall of the hole 19.

Holes 65 to 68, which are aligned with the threaded holes 61 to 64, areprovided in the mounting plate 13 for insertion of a tool for theadjusting screws in the threaded holes 61 to 64. Holes 69,70 are usedfor mounting on the mounting block 6 (FIG. 1). An elongated cutout 71exposes the line sensor 15 for the incident light.

What is claimed is:
 1. Apparatus for adjusting a line sensor in a filmscanner comprising: a colour splitter for splitting the image into theprimary colours; a line sensor for each primary colour, and a glass panefor each line sensor for adjusting the horizontal and vertical positionsof the film line which is imaged on the sensor, a holder for holding theglass pane, mounted at three points, with two points being adjustablesuch that the glass pane can be pivoted in two directions from a planeat right angles to the beam direction, and the light emerges offset fromthe glass pane as a function of the pivoting angle.
 2. Apparatusaccording to claim 1, wherein the pivoting directions are essentially atright angles to one another.
 3. Apparatus according to claim 2, whereinone contact point is provided jointly for both pivoting directions. 4.Apparatus according to claim 1, wherein the holder is mounted on a fixedholding point of a housing such that it can pivot, with the holderhaving two inclines on each of which an adjusting screw, which ismounted in the housing, acts such that the holder can be adjusted in twodirections against the spring force of a spring between the holder andthe housing.
 5. Apparatus according to claim 1, wherein the line sensoris arranged on a mount which can pivot about an axis parallel to thelines.
 6. Apparatus according to claim 5, wherein the mount is providedwith an incline on the side of the line sensor opposite the pivotingaxis, on which incline an adjusting screw acts against a spring force.7. Apparatus according to claim 1, wherein the line sensor is arrangedon the mount by means of a sensor holder, such that the sensor holderhas two pins in an extension of the longitudinal axis (line direction)of the line sensor, which pins project into holes in the mount and haveplay at right angles to the line direction, and in that an adjustingscrew projects into the hole from each of the two sides.
 8. Apparatusaccording to claim 7, wherein the pins are flattened on one side.